A number of balance devices have been disclosed in which the user stands on a board resting on a roller, and tries to keep the board balanced on the roller, which is on a supporting surface, such as a floor.
Examples of U.S. Patents which disclose balance devices of this type are:
U.S. Pat. No.Issue DateInventor2,764,411Sep. 25, 1956S. Washburn, Jr.2,829,892Apr. 8, 1958F. G. Ludwig3,630,540Dec. 28, 1971William J. Smith4,505,477Mar. 19, 1985John M. Wilkinson4,601,469Jul. 22, 1986Martin Sasser, Jr.4,911,440Mar. 27, 1990Hyman, et al.5,152,691Oct. 6, 1992Bruce P. Moscarello5,190,506Mar. 2, 1993Zubik, et al.
The prior art balance devices are of complex construction, and provide only one degree of difficulty in using the device. Thus, a beginner has difficulty in mastering the prior art devices, and is exposed to potentially dangerous accidents.